#include <bits/stdc++.h>
#include <deque>
using namespace std;
int main()
{
	deque<int> dq;
	
	dq.push_back(20);
	
	dq.push_back(30);
	
	dq.push_back(10);
	
	cout << "头部元素：" << dq.front() << endl;
	cout << "尾部元素：" << dq.back() << endl;
	
	dq.pop_front();
	
	cout << "索引1的值：" << dq[1] << endl;
	return 0;
}